Having a large aquarium means a lot of scraping of glass as part of the regular maintenance. If like me, you have a marine aquarium, this can mean a build up of both green soft algae and coralline algae, the hard purple calcium deposit. The shop bought scrapers work great but blunt quickly and have expensive blades. So as my first design and print ever... here is my stanley knife blade scraper. Design may change soon as this is a prototype! Print both parts, I just used standard print from my new Davinci. Sandwich a stanley blade between the two pieces on the little lugs and clamp with your choice of fixings. I have used 3mm plastic pop rivets, but you could use plastic nuts and bolts (printed maybe) or stainless steel, just don't use brass or copper as these can be toxic to fish and coral...... Feel free to comment....